The acid-catalysed transformation of light olefins was studied at various temperatures and partial pressures over ZSM-5 of varying acidic contents. It was observed that, as the temperature increased, the rate of consumption of ethene and propene decreased, whereas the rate of consumption of butene increased. Despite the fact that this reaction proceeds by a rather complex network mechanism, a single kinetic model describing the rate of consumption of the three reactants was developed, with the explicit inclusion of the step corresponding to the adsorption of the reactant molecules.

Graphical abstractThe acid-catalysed transformation of light olefins (ethylene, propylene, and butene) was studied at various temperatures and partial pressures over ZSM-5 with varying acidic contents. A single kinetic model describing the rate of consumption of the three reactants as a function of temperature and pressure was developed. Apparent negative activation energies were observed which are related to adsorption enthalpy of the reactants, possible intermediates, and confinement effects but not catalyst deactivation. Results shown in the graph are for the conversion of propylene.Figure optionsDownload full-size imageDownload as PowerPoint slide